Magnetic pull up machine for positioning and lineal measurement of magnetic strip material



w G. MOSHER ETAL 3,137,190

MAGNETIC PULL UP MACHINE FOR POSITIONING AND LINEAL MEASUREMENT OF MAGNETIC STRIP MATERIAL Original Filed June 4, 1962 June 16, 1964 70 OTHER I PROX/M/W j ELEMENT 32-- AMPLIFIER RELAY 70 OTHER 14 mRqz-"rw/L I I I 4 POWER SUPPLY I 23 [m nfirs,

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3,137,190 MAoNnrrc PULL or MAcrrmn son POSiTiQN ENG AND LINEAL MEASUREMENT F MAG NETIC STREP MATERIAL Wesson G. Mosher, Huntington, Conn., and Alexander J.

Kazura, Pittsiield, Mass, assignors to General Electric Q Company, a corporation of New York Continuation of application Ser. No. 199,889, lane 4,

1962. This application June 27, 1963, Ser. No. 292,812

3 Claims. (Cl. 83-210) This invention relates to a novel automatic machine for pulling up strip material and accurately measuring its length preparatory to cutting it into pieces or" predetermined length and more particularly to a new and improved machine of this type for producing magnetic steel transformer core lamination pieces.

This is a continuation of application Serial Number 199,889, filed June 4, 1962, now abandoned.

Magnetic core lamination pieces are conventionally cut to length from a roll of magnetic strip material asreceived from the steel mill. As a great many lamination pieces are ordinarily used to make each transformer core, it is desirable that the measuring and cutting operation be performed as rapidly as possible, and it is equally important that the length measurement be as accurate as possible so as not to waste material or affect the magnetic performance of the core. The roll of steel as it is received from the steel mill often has ripples or waves which make it difficult accurately to measure the true lineal length of each piece. This, however, is important because the lamination pieces in a transformer core are usually clamped tightlytogether and thus the ripples or waves are effectively ironed out. Conventional machines for pulling up the strip and measuring its length preparatory to cutting also involve problems of stopping the strip without injury to its advancing edge such as by impact between the fast moving advancing edge and a fixed stop. 7

Another problem with conventional strip pull up and lineal measurement machines is that of cutting pieces of varying lengths and conventionally whenever a change in length is desired, it is necessary to shut the machine down and set it for the new length pieces.

In accordance with this invention, there is provided a novel and simple machine i-or eliminating these problems and making it possible to cut very accurately at very high speed pieces of any desirable length- Briefly, this is accomplished by means of a movable electromagnetic bed for controlling the strip in combination with a proximity pick up for sensing the approach of the advancing edge of the strip and automatically making certain changes in the operation of the machine in combination with a target switch element for making certain other changes in the operation of the machine and causing the strip to be cut at exactly therdesired length.

An object of the invention is to provide a new and improved pull up machine for accurately positioning and lineally measuring magnetic strip material.

The invention will be better understood from the follow- 3,137,190 Patented June 16, 1964 2 strip produced by thepresent invention when themeasuring and cutting operation take place. Referring now to the drawing and more particularly to FIG. 1, the machine proper is indicated generally by the reference character 1. For supplying this machine with strip steel there is shown an unreeler 2, a back tension and slack controlling loop 3 and a pair of so-called pinch rolls 4 between which the strip 5 passes and which are driven at comparatively high speed so as to advance the strip 5 at a speed of typically 500 feet per minute over a bed 6 for a cutting shear or knife 7 suspended thereabove. The shear 7 is normally in its raised position and may be plunged downwardly at controlled times by any suitable means such as an air cylinder 8 having interconnected valves 9 for controlling the admission of air pressure to opposite sides of its piston. A spring 10 normally maintains those valves in the position for maintaining the shear blade 7 raised and an electromagnetic coil 11 is provided which when energized overcomes the spring and operates the valves to plunge the cutting shear 7 downwardly across the strip 5. Thus deenergizing of the operating coil 11 permits the spring to operate the valves'so as to return the cutting shear 7 to its raised position. I

The pinch rolls 4 are movable into engagement with the strip 5 and disengagement therefrom by suitable means such as double air cylinders 12 provided with valve operating coils 13 for causing the rolls to move toward each other to pinch the strip 5 therebetween and valve controlling coils 14 which when energized cause the air cylinders 12 to separate the pnich rolls so that they are no longer in driving engagement with the strip 5.

The parts thus far described for supplying strip material to the cutting shear 6-7 and the cutting shear itself are conventional and well known and, strictly speaking, form no part of the present invention, except that they, or their equivalent are necessary for the proper operation of the novel pull up and positioning machine which constitute the invention proper.

As viewed in FIGS. 1 and 2, the machine 1 comprises a traveling electromagnetic bed preferably in the form of a plurality of electromagnets 15. These electromagnets are generally similar in construction to conventional scrap lifting electromagnets, except that their pole faces are generally elongated in shape. Thus they each oomprise an outer pole 16 and inner pole 17 between which is located an energizing coil 18. If desired, these poles may be covered by a flat sheet of non-magnetic material. The electromagnets 15 constituting the electromagnetic bed are slidable on rods 19 and are yoked together for back and forth movement in the direction of the motion of the strip 5 by any suitable means such as another air cylinder 2t) having an operating coil 21 for controlling a valve for causing motion of the magnetic bed in the direction of the strip 5 and a coil 22'for controlling a valve for reversing the direction of the bed. The overall length of the magnetic bed is preferably substantially equal to the length of the longest piece to be cut by the machine. The speed of movement of the magnetic bed is much slower than the speed of movement of the strip 5 produced by the pinch rolls 4 and is typically of the order of forty feet per minute. The range of movement of the magnetic bed is typically very much shorter than its length, being typically six inches of movement as compared with a typical bed length of say two hundred inches.

'As shown most clearly in FIG. 2 a control element or module 23 is mounted between the electromagnets 15 constituting the magnetic bed. Mounted in this module is a proximity pick up 24 which consists essentially of an sulated plunger 28 which is raised from a position beneath the surface of the magnetic bed to a position above it and in the path of movement of the advancing edge of the strip by energization of the magnetic coil 27. If desired, additional duplicate control modules 23"and 23 may be aligned with the module 23 between the magnets 15. They may all be fastened together for uniform vernier adjustment motion in a direction corresponding to the direction of motion of the strip 5 by any suitable means, such as a screw threaded shaft 29 which may be rotated by any suitable means so as to move the modules 23 by the desired amount. As shown for the sake of simplicity, the operating means is a simple handwheel 30 which may be indexed so that its angular position will give indication of the lineal position of the modules 23. Typically thelineal spacing between the proximity pick ups 24 and the target switch element 26 of each module is the same and is approximately equal to the range of lineal travel of the magnetic bed. In each module the proximity pick up 24 is nearest the shear 6 and the target element 26 is farthest from the shear 7.

' The electrical connections of the machine are shown in FIG. 3 wherein a multi-throw switch 31 is shown connecting the proximity pick up coil 25 to the input of an amplifier relay 32 which is supplied with power in any suitable manner such as from the positive side of a power supply source 33 whose other side is grounded. As indicated, the switch 31 may be thrown to other positions for connecting the amplifier 32 to any one of the other pick up coils 25 in the proximity elements 24 of the other modules, such as 23' and 23". Likewise, a multi-throw switch 34 is shown in the position for energizing the coil 27 of the target switch element 26 for raising the insulated plunger 28 above the magnetic bed and into the path of movement of the strip 5. As indicated, this switch may be moved to other positions for deenergizing the coil 27 thus permitting its plunger 28 to fall below the surface of the magnetic bed while energizing a corresponding operating coil of any other target switch element of the other modules 23, 23, etc.

The coil 11 for causing operation of the shear 7, the coils 13 for causing closing of the pinch rolls 4 and the coil 22 for controlling the return movement of the magnetic bed have their energization and deenergization controlled by contact between the advancing end of the strip 5 and the insulated plunger 28. Thus as shown in FIG. 3 the circuit may be from the positive side of the power supply 33 through coils 11, 13, and 22 in parallel to the insulated target switch plunger 28.

As shown in FIG. 1, the unreeler 2 for paying the strip 5 from a roll is grounded so that when the advancing end of the strip 5 strikes the insulated contact 28 a circuit is completed for energizing the coils 11, 13 and 22 and at other times these coils are deenergized.

The proximity pick up coil 25 is supplied with current from the amplifier 32 so as to produce a magnetic field indicated by the dotted lines 34' and the reluctance of the magnetic circuit of this coil and hence its effective reactance is varied when the advancing end of the magnetic strip 5 passes through that magnetic field. Amplifier 32 responds to this change in reluctance in a well-known manner to open and close a circuit 35 energized from across the current supply source 33. Circuit 35 includes the coils 14 for controlling the opening of the pinch rolls and thecoil 21 for controlling the advance movement of the magnetic bed and an additional coil 36 for operating a timer control 37 which in turn controls the energization of the coils 18 of the electromagnets constituting the electromagnetic bed. The timer control is such that a definite minimum amount of current from the power supply 33 always flows through the coils 18 of the electromagnets 15. However, when the magnetic control coil 36 is energized by actuation of the proximity control, the energization of the magnet coil 18 is transiently increased tomany times its minimum value and then al- A; lowed to decay at a predetermined time rate to its minimum value.

The operation of the illustrated embodiment of the 1nvention is as follows.

As shown in FIG. 1, the strip 5 is being advanced from left to right, as indicated by the arrow, between pinch rolls 4 and its advancing end has passed under the shear blade 7 and has just reached the left-hand end of the magnetic bed when the latter is in its retracted position illustrated by the solid lines. As indicated by the upper line A in FIG. 4 the strip 5 normally has ripples or waves and is not absolutely fiat as it comes from the pinch rolls 4. It has been found that at high speeds, such as five hundred feet per minute, that not infrequently air gets under the advancing end of the strip causing what is called airplaning, i.e., the strip rises and tends to flutter about making it diflicult to control. However, in the present invention, the magnetic bed consisting of the magnets 15 1s continuously energized at a minimum level sufficient to the strip slides smoothly along the magnetic bed without bulging or buckling as it is pushed ahead from the pinch rolls 4. In general, the narrower the strip 5 the less tendency there is for it to airplane and the more tendency there is for it to buckle between the pinch rolls 4 and the magnetic bed so that in general the narrower the strip the lower the minimum energization of the magnets should be. When the strip reaches the neighborhood of the proximity element 24 it alters the magnetic field 34 of the coil 25 so as to change its circuit constants and cause actuation of the amplifier relay 32. This in turn causes energization of the coils 14 for separating the pinch rolls 4 so that the strip is no longer advanced by the pinch rolls. At the same time the coil 21 is energized for causing the magnetic bed to move forward in the direction the strip has been traveling but at much slower speed. Also, at the same time the coil 36 is energized for actuating the timer control 37 which functions to greatly increase the energization of the coils 18 of the electromagnets 15. Consequently, the strip 5 is clamped firmly to the magnetic bed and is advanced by the forward motion of the magnetic bed. The magnetic clamping action tends to flatten out the strip as shown by the lower straight line AB in FIG. 4 and this is important for obtaining accurate lineal measurement of pieces to be cut from the strip.

The timer control 3'7 also reduces the energization of the magnets 18 when the advancing end of the strip 5 is about to contact the target element 28 so that the clamping action is somewhat relaxed and there will be no impact hard enough to damage the advancing end of the strip. As soon as the advancing end of the strip 5 touches the target element 28 the latter is in effect electrically grounded thus completing a circuit from the positive side of the power supply to ground through the shear operating coil 11 thus causing the blade 7 to sever the strip and produce a piece of exactly the desired length as determined by lineal distance between theblade 7 and the target element 28. At the same time the pinch roll closing coils 13 are energized and the coil 22 for causing return motion of the magnetic bed is energized.

As soon as a piece is cut by the blade 7 from the strip 5 this piece is removed by any suitable means such as manually by an operator or by suitable automatic means which form no part of the present invention.

The machine is then ready for another cycle of operation as has just been described for cutting another piece and this action can be continued as long as desired.

If it is desired to cut shorter pieces then the switches 31 and 34 can be operated to activate the respective proximity and target elements in other control modules such as 23' or 23". These switches 31' and 34 can be operated manually or their operation can be programmed automatically by means of tapes or punch cards in any manner now well known to the art. As shifting the control from one module to another will provide pieces of strip differing in length by the lineal separation of the modules intermediate variations in length can be obtained by rotating the indexed knob 30 so as to cause modules 23 to move in a lineal direction so that they can be positioned with what amounts to micrometer accuracy. As will be appreciated, this latter adjustment need only have a range corresponding to the lineal dimensions of the modules so that it is in effect a Vernier adjustment which is common to and can be used with any one of the actuated control modules.

While there has been shown and described a particular embodiment of the invention, it will be obvious to those skilled in the art that changes and modifications may be a predetermined distance from said cutting means on the opposite side thereof from said driving means in the path of movement of said strip, an electromagnetic supporting bedfor said strip normally insufficiently energized to prevent the advancing end of said strip from advancing at high speed across its poles, means responsive to the end of said strip reaching said circuit controller for (a) inactivating said driving means so that it no longer moves saidstrip (b) moving said magnetic supporting bed in the direction said strip has been traveling but at greatly reduced speed and (,0) strongly energizing said magnetic supporting bed for magnetically pulling up and flattening outsaid strip by firmly magnetically clamping it to the moving bed, a target element in the form of an electrical contact in the path of movement of said strip a predetermined distance away jrom said cutting means beyond said circuit'controller, and means responsive to the advancing endof said strip reaching said target element for (a) operating said cutting means to sever said strip, (12) reactivating said driving means for continuedhigh speed advancement of said strip, and (c) returning said magnetic bed to, its initial position in its initial condition.

,2.A magnetic pull up for accurate positioning and lineal measurement of thin strip steel as it is moved ithrough a cutting shear by high speed pinch rolls from an unreeler and a gravity suspended back tension controlling slack takeup loop comprising, in combination, a

proximity pick up located a predetermined distance from said shear on the opposite sidethereof from said pinch rolls in the path of movement of said strip, an electromagnetic supporting bed for said strip normally insuificiently energized to prevent the advancing end of said strip from advancing at high speed across its poles, means responsive to the advancing end of said strip reaching the proximity of said pick up for (a) separating said pinch rolls so that they no longer move said strip (11) moving said magnetic supporting bed in the direction said strip 'has been traveling but at greatly reduced speed and (c) transiently strongly energizing said magnetic supporting bed but with a time decay in said energization for magnetically pulling up and flattening out said strip'by firmly magnetically clamping it to the moving bed, a target ele- V ment in the form of a combination mechanical stop and electrical contact in the path of movement of said strip a predetermined distance away from said shear beyond said proximity pick up, and means responsive to the advancingend of said strip touching said target element for a (a) operating said shear to sever said strip, (b) bringing said pinch rolls together for continued high speed adfi vancement of said strip, and (c) returning said magnetic bed to its initial position in its initial condition.

3. A magnetic pull up for accurate positioning and lineal measurement of thin strip steel as it is moved through a cutting means by high speed driving means comprising, in combination, a circuit controller located a predetermined distance from said cutting means on the opposite side thereof from said driving means in the path of movement of said strip, an electromagnetic supporting bed for said strip normally insufficiently energized to prevent the advancing end of said strip from advancing at high speed across its poles, means responsive to the end of said strip reaching said circuit, controller for (a) inactivating said driving means so that it no longer moves said strip ([2) moving said magnetic supporting bed in the direction said strip has been traveling but at greatly reduced speed and (0) strongly energizing said magnetic supporting bed for magnetically pulling up and flattening out said strip by firmly magnetically clamping it to the moving bed, a target element in the form of an electrical contact in the path ofmovement of said strip a predetermined distance away from said cutting means beyond said circuit controller, means responsive to the advancing end of said strip reaching said target element for (a) operating said cutting means to sever said strip, (19) reactivating said driving means for continuedhigh speed advancement of said strip, and (c) returning said magnetic bed to its initial position in its initial condition, a second circuit controller and target element spaced apart substantially the same distance as the first mentioned circuit controller and target element and aligned therewith in the direction of motion of said strip, and means for selectively incapacitating the first mentioned circuit controller and target element and causing the second circuit controller and target elements to perform the respective functions of the first mentioned circuit controller and target element so that different length pieces of said strip can selectively be magnetically pulled up and measured preparatory to cutting.

4. A magnetic pull up for accurate positioning and lineal measurement of thin strip steel as it is moved through a cutting shear by high speed pinch rolls from an unreeler and a gravity suspended back tension controlling slack take-up loop comprising, in combination, an electromagnetic proximity pick up located a predetermined distance from said shear on the opposite side thereof from said pinch rolls in the path of movement of said strip, an

electromagnetic supporting bed for said strip normally insufiiciently energized for preventing the advancing end of said strip from advancing at high speed across its' poles, means responsive to the advancing end of said strip reaching the proximity of said pick up for (a) separating said pinch rolls so that they no longer move said strip (b) moving said magnetic supporting bed in the direction said strip has been traveling but at greatly reduced speed and (c) transiently strongly energizing said magnetic supporting bed but with a time decay in said energization for magnetically pulling up and flattening out'saidstrip by firmly magnetically clamping it to the moving bed, a target element in the form of a combination of a mechanical stop and electrical contact in the path of movement of said strip a predetermined distance away from said shear beyond said proximity pick up, means responsive to the advancing end of said strip touching said target element for (a) operating said shear to sever said strip, (b) bringing said pinch rolls together for continued high speed advancement of said strip, and (c) returning said magnetic bed toits initial position in its initial condition, a second proximity pick up and target element spaced apart substantially the same distance as the first mentioned proximity pick up and target element and aligned therewith in the direction of motion of said strip, and means for selectively incapacitating the first mentioned proximity pick up and target element and causing thesecond proximity pick up and target elements to perform the respec- U tive functions of the first mentioned proximity pick up and target element so that different length pieces of said strip can selectively be magnetically pulled up and measured preparaotry to cutting, said electromagnetic bed being substantially as long as the distance from said shear to the most remote target element, and means for simultane'ously and equally varying the spacing of said pick ups and target elements from said cutting shear a distance substantially equal to the distance between the first and second target elements for providing a vernier like adjustment in the length of pieces of said strip which are pulled up and measured preparatory to cutting.

5. A magnetic pull up for accurate positioning and lineal measurement of thin strip steel as it is moved through a cutting means by high speed driving means comprising, in combination, a proximity pick up located a predetermined distance from said cutting means on the opposite side thereof from said driving means in the path of movement of said strip, an electromagnetic supporting bed for said strip normally weakly energized for preventing airplaning of the advancing end of said strip while permitting said strip to advance at high speed across its poles, means responsive to the end of said strip reaching the proximity of said pick up for (a) inactivating said driving means so that it no longer moves said strip (b) moving said magnetic supporting bed in the direction said strip has been traveling but at greatly reduced speed and (c) transiently greatly increasing the energization of said magnetic supporting bed for magnetically pulling up and flattening out said strip by firmly magnetically clamping it to the moving bed, a target element in the form of a combination mechanical stop and electrical contact in the path of movement of said strip a predetermined distance away from said cutting means beyond said proximity pick up, and means responsive to the advancing end of said strip touching said target element for (a) operating said cutting means to sever said strip, (b)reactivating said driving means for continued high speed advancement of said strip, and (c) returning said magnetic bed to its initial position.

6. A magnetic pull up for accurate positioning and lineal measurement of thin strip steel as it is moved through a cutting shear by high speed pinch rolls from an unreeler and a gravity suspended back tension controlling slack takeup loop comprising, in combination, a proximity pick up located a predetermined distance from said shear on the opposite side thereof from said pinch rolls in the path of movement of said strip, an electromagnetic supporting bed for said strip normally weakly energized for preventing airplaning of the advancing end of said strip while permitting said strip to advance at high speed across its poles, means responsive to the advancing end of said strip reaching the proximity of said pick up for (a) separating said pinch rolls so that-they no longer move said strip (b) moving said magnetic supporting bed in the direction said strip has been traveling but at greatly reduced speed and (c) transiently greatly increasing the energization of said magnetic supporting bed but with a time decay in said increased energization for magnetically pulling up and flattening out said strip by firmly magnetically clamping it to the moving bed, a target element in the form of a combination mechanical stop and electrical contact in the path of movement of said strip a pre determined distance away from said shear beyond said proximity pickup, and means responsive to the advancing end of said strip touching said target for (01) operating said shear to sever said strip, (b) bringing said pinch rolls together for continued high speed advancement of said strip, and (c) returning said magnetic bed to its initial position.

7. A magnetic pull up for accurate positioning and lineal measurement of thin strip steel as it is moved through av cutting means by high speed driving means comprising, in combination, a proximity pick up located a predetermined distance from said cutting means on the opposite side thereof from said driving means in the path of movement of said strip, an electromagnetic supporting bed for said strip normally weakly energized for preventing airplaning of the advancing end of said strip while permitting said strip to advance at high speed across its poles, means responsive to the end of said strip reaching the proximity of said pick up for (a) inactivating said driving means so that it no longer moves said strip (b) moving said magnetic supporting bed in the direction said strip has been traveling but at greatlyreduced speed and (c) transiently greatly increasing the energization of said magnetic supporting bed for magnetically pulling up and flattening out said strip by firmly magnetically clamping it to the moving bed, a target element in the form of a combination of a mechanical stop and electrical contact in the path of movement of said strip a predetermined distance away from said cutting means beyond said proximity pick up, means responsive to the advancing end of said strip touching said target element for (a) operating said cutting means to sever said strip, (b) reactivating said driving means for continued high speed advancement of said strip, and (c) returning said magnetic bed to its initial position, a second proximity pick up and target element spaced apart substantially the same distance as the first mentioned proximity pick up and target element and aligned therewith in the direction of motion of said strip, and means for selectively incapacitating the first mentioned proximity pick up and target element and causing the second proximity pick up and target elements to perform the respective functions of the first mentioned proximity pick up and target element so that different length pieces of said strip can selectively be pulled up and measured preparatory to cutting.

8. A magnetic pull up for accurate positioning and lineal measurement of thin strip steel as it is moved through a cutting shear by high speed pinch rolls from an unreeler and a gravity suspended back tension controlling slack take-up loop comprising, in combination, and electromagnetic proximity pick up located a predetermined distance from said shear on the opposite side thereof from said pinch rolls in the path of movement of said strip, an electromagnetic supporting bed for said strip normally weakly energized for preventing airplaning of the advancing end of said strip while permitting said strip to advance at high speed across its poles, means responsive to the advancing end of said strip reaching the proximity of said pick up for (a) separating said pinch rolls so that they no longer move said strip (b) moving said magnetic supporting bed in the direction said strip has been traveling but at greatly reduced speed and (c) transiently greatly increasing the energization of said magnetic supporting bed but with a time decay in said increased energization for magnetically pulling up and flattening out said strip by firmly magnetically clamping-it to the moving bed, a target element in the form of a combination of a mechanical stop and electrical contact in the path of movement of said strip a predetermined distance away from said shear beyond said proximity pick up, means responsive to the advancing end of said strip touching said target element for (a) operating said shear to sever said strip, (b) bringing said pinch rolls together for continued high speed advancement of said strip, and (0) returning said magnetic bed to its initial position, a second proximity pick up and target element spaced apart substantially the same distance as the first mentioned proximity pick up and target element and aligned therewith in the direction of motion of said strip, and means for selectively incapacitating the first mentioned proximity pick up and target element and causing the second proximity pick up and target elements to perform the respective functions of the first mentioned proximity pick up and target element so that different length pieces of said strip can selectively be pulled up and measured preparatory to cutting, said electromagnetic bed being substantially as long as the distance from said shear to the most i emote target element, and means for simultaneously and equally varying the spacing of said pick ups and target elements from said cutting shear a distance substantially 7 equal to the distance between the first and second target elements for providing a yernier like adjustment in the length of pieces of said strip which are pulled up and measured preparatory to cutting.

10 References Cited in the file of this patent UNITED STATES PATENTS Reed Nov. 21, 1922 

1. A MAGNETIC PULL UP FOR ACCURATE POSITIONING AND LINEAL MEASUREMENT OF THIN STRIP STEEL AS IT IS MOVED THROUGH A CUTTING MEANS BY HIGH SPEED DRIVING MEANS COMPRISING IN COMBINATION, A CIRCUIT CONTROLLER LOCATED A PREDETERMINED DISTANCE FROM SAID CUTTING MEANS ON THE OPPOSITE SIDE THEREOF FROM SAID DRIVING MEANS IN THE PATH OF MOVEMENT OF SAID STRIP, AN ELECTROMAGNETIC SUPPORTING BED FOR SAID STRIP NORMALLY INSUFFICIENTLY ENERGIZED TO PREVENT THE ADVANCING END OF SAID STRIP ADVANCING AT HIGH SPEED ACROSS ITS POLES, MEANS RESPONSIVE TO THE END OF SAID STRIP REACHING SAID CIRCUIT CONTROLLER FOR (A) INACTIVATING SAID DRIVING MEANS SO THAT IT NO LONGER MOVES SAID STRIP (B) MOVING SAID MAGNETIC SUPPORTING BED IN THE DIRECTION SAID STRIP HAS BEEN TRAVELING BUT AT GREATLY REDUCED SPEED AND (C) STRONGLY ENERGIZING SAID MAGNETIC SUPPORTING BED FOR MAGNETICALLY PULLING UP AND FLATTENING OUT SAID STRIP BY FIRMLY MAGNETICALLY CLAMPING IT TO THE MOVING BED, A TARGET ELEMENT IN THE FORM OF AN ELECTRICAL CONTACT IN THE PATH OF MOVEMENT OF SAID STRIP A PREDETERMINED DISTANCE AWAY FROM SAID CUTTING MEANS BEYOND SAID CIRCUIT CONTROLLER, AND MEANS RESPONSIVE TO THE ADVANCING END OF SAID STRIP REACHING SAID TARGET ELEMENT FOR (A) OPERATING SAID CUTTING MEANS TO SEVER SAID STRIP, (B) REACTIVATING SAID DRIVING MEANS FOR CONTINUED HIGH SPEED ADVANCEMENT OF SAID STRIP AND (C) RETURNING SAID MAGNETIC BED TO ITS INITIAL POSITION IN ITS INITIAL CONDITION. 